One of the major advances in communications in recent years has been the increased use of optical fiber systems for carrying very large quantities of information with low distortion and low cost over great distances. Optical systems are also promising for such purposes as computing and switching because of the inherently high speeds at which they can be operated. For these reasons, considerable work has been expended to develop convenient techniques for operating directly on transmitting information-carrying light to produce various device functions, that is, without converting such light to electrical energy prior to such operations. The utilizing of such devices will depend to a great extent on the efficiency and facility with which they can be made.
Optical fibers typically comprise a core of relatively high refractive index glass having a diameter of five microns surrounded by low refractive index glass having a diameter of one hundred twenty-five microns. The paper, "All-Optical Implementation of a 3-D Crossover Switching Network," by T. J. Cloonan et al., IEEE Photonics Technology Letters, Vol. 2, No. 6, June 1990, pp. 438-440, describes a free-space photonics switch which takes light from the end of a bundle of optical fibers, operates on the light so as to perform desired switching functions, and then projects the light into the end of a second array of optical fibers. The optical fiber ends of each bundle form a matrix configuration which must be accurately registered with the other apparatus. Because the size of each fiber, especially the core, is so small, it is important that the ends of each optical fiber bundle be positioned with a great deal of accuracy; fixing the ends of an optic fiber bundle in a desired matrix configuration with the precision needed for such functions as free-space photonics switching is difficult and painstaking.
Because of their importance both to communications and to high-speed computing, there has been a long-felt need in the industry for techniques that can be used to arrange the ends of optical fibers in a desired configuration, that are relatively inexpensive, that do not require a great deal of operator skill, and that are dependably accurate to within micron or sub-micron dimensions.